Inner tube for pneumatic tires



N. G. WARTH. Y NERITUBE FOR PNEUMATIC TIRES"I APPLICATION FxLED JULY 1s,1919.`

Patented Sept. 19

Fig. 3.

` l 5mm/coz Nathaniel G.Wa1fth 1 HOWWS l Patented Sept. 19, 1922.

UNITED STATES i terasse NATHANIEL Gr. WARTH, OF COLUMBUS, OHIO.

' INNER TUBE FOB PNEUMATIC TIRES.

Application filed July 18,

T all whom t may concern:

Be it known that I, NATHANIEL Gr. WARTH, a citizen of the United States,residing at Columbus, in the county of Franklin and State of Ohio, haveinvented a certain new and useful Improvement inlnner Tubes forPneumatic Tires7 of which the following is a specification. v

The object of this invention is to provide 10 an improved form of innertube for a pneumatic tire adapted to lessen the evils of puncturing. y

The invention is embodied in the example herein shown and described, thefeatures of novelty being finally claimed.

In the accompanying drawing- Figure l is a cross section of the tubeaccording to my invention.

Fig. 2 is a similar section illustrating the same lodged in a tirecasing but before inllation.

Fig. 3 is a view like Fig. 2 showing the tube inflated.

In the views 6 designates the inner tube.

Such tube is formed of soft rubber in a circular vulcanizing mold andwithout joints or seams, and so that it comes from the mold round orcircular in form conforming normally circumferentially to the cavity ofthe casing except as to the annular outward projection hereinafterreferred to.

The tube is also equipped with the usual valve stem (not shown) foriniating it, said stem having a suitable reinforcing mounting placed inthe tube prior to the process of vulcanizing it.

The tube at its inner side is molded with a circumferential outwardprotrusion 8 formed upon a curve of smaller radius than that of thecross section of the main body of the tube or so as to contain morerubber at its region than if that portion were made on the aforesaidradius of the tube. The tube is preferably made in its major portion to45 iit closely the casing 7 when in uninflated condition or as shown inFig. 2. Hence when such a tube is inliated against the resisting casingand wheel rim the puckered portions of the tube paralleling the portion8 are forced outward into coincidence with the cavity formed by thecasing and rim as shown in Fi 3. When so forced out a condensation o therubber takes place principally in the region of the wheel but 1919.serial No. 311,860.

said condensation effect is distributed both circumferentially asrespects the entire tube as well as respects its cross section orlaterally toward the tread region. In the present instance, therefore,the tube` when iniated in such a casing when mounted on a rim issubjected to a double condensationl/Vhen placed in every directionagainst the resisting walls of the casing with the result that when auobject penetrating the tube is removed the material reacts or expands inthe perforation to close the same and prevent the es cape of theinflating air. In most i instances the presence of the condensedmaterial of the tube around the puncturing thing even when no-t removedis sufficient to prevent the deflation of the tube. Vith thisconstruction, therefore, much of the trouble, expense and delay incidentto tire puncturing and fiat tire Vis avoided.

The form of the embodiment of the inven-4 tion can be varied to someextent without.

departing from the gist of the invention as claimed.

l/Vhat I claim is:

An inner tube of soft rubber for a pneumatic tire having its main bodyportion substantially permanently circular in cross section and providedat its inner side with a circumferential outward protrusion from y themain body portion said protrusion havin the casing and suliiciently linflated the walls of the tube are condensed adapted when inserted inthe casing and rim to form at each side thereof circumferential inwardprotrusionssubject to compression when the tube is inflated.

NATHANIEL G. WARTH.

